Explanation
OFDMA (Orthogonal Frequency Division Multiple Access) is a technology that can minimize client latency in a high-density environment by eliminating contention overhead by dedicating subcarriers to clients. OFDMA allows multiple clients to transmit simultaneously on different subcarriers within the same channel, reducing contention and increasing efficiency. MU-MIMO (Multi-User Multiple Input Multiple Output) is a technology that allows multiple clients to transmit simultaneously on different spatial streams within the same channel, but it does not eliminate contention overhead. QWMM (Quality of Service Wireless Multimedia) is a technology that prioritizes traffic based on four access categories, but it does not eliminate contention overhead. Channel Bonding is a technology that combines two adjacent channels into one wider channel, increasing bandwidth but not eliminating contention overhead. References:
https://www.arubanetworks.com/assets/ds/DS_AP510Series.pdf
https://www.arubanetworks.com/assets/wp/WP_WiFi6.pdf

Explanation

https://www.arubanetworks.com/techdocs/Instant_85_WebHelp/Content/instant-ug/wlan-ssid-conf/conf-fast-roa

Explanation
According to the Aruba Documentation Portal1, the firewall role derivation flow in the correct order is:
* Server derived role
* User derived role
* Authentication default role
* Initiation role assigned

According to the Aruba Documentation Portal1, 802.1X is a standard for port-based network access control that uses a RADIUS server to authenticate and authorize wireless clients. 802.1X can be configured in different modes, such as bridge mode, tunnel mode, or split tunnel mode.
Option C: GRE tunnel
This is because option C shows how to configure an SSID in tunnel mode with the default AP-group settings on an Aruba switch. In tunnel mode, all client traffic from the access points is tunneled back to the controller and the controller would in turn put the client traffic onto the network2. The GRE protocol is used to encapsulate and decapsulate the traffic between the access points and the controller3.
Therefore, option C is correct.
1: https://www.arubanetworks.com/techdocs/AOS-CX/10.06/HTML/5200-7696/GUID-581D2976-694B-46C7-8497-F6B788AA05B2.html 2: https://community.arubanetworks.com/discussion/bridge-and-tunnel-mode 3: https://www.twingate.com/blog/ipsec-tunnel-mode

The correct answer is C. sysops.
The sysops user role is a predefined role that allows users to view switch configuration information and have access to the PUT and POST methods for REST API. The sysops user role can also use the PATCH and DELETE methods for REST API, but not for all resources. The sysops user role is suitable for users who need to perform system operations on the switch, such as backup, restore, upgrade, or reboot.
According to the AOS-CX REST API Reference basics1, one of the predefined user roles is: sysops:
Users with this role can view switch configuration information and have access to the PUT and POST methods for REST API. They can also use the PATCH and DELETE methods for REST API, but not for all resources. Users with this role can perform system operations on the switch, such as backup, restore, upgrade, or reboot.
The other options are incorrect because:
A) administrators: Users with this role have full access to all switch configuration information and all REST API methods. This role is more than what the customer requires.
B) auditors: Users with this role can only view switch configuration information and have access to the GET method for REST API. They cannot use the PUT and POST methods for REST API.
D) helpdesk: Users with this role can view switch configuration information and have access to the GET method for REST API. They can also use the PATCH method for REST API, but only for a limited set of resources. They cannot use the PUT and POST methods for REST API.